In the automotive industry, it is desirable to extend the life of vehicle bodies by protecting them from, for example, the abrasive chipping action of road dirt and debris, such as sand and gravel, that may cause an aesthetically unpleasing chipping of the vehicle body surface, which may also lead to rusting. Often, coating compositions designed to aid in various properties, such as corrosion resistance and chip resistance are employed to protect against such damage. Thus, coating compositions, such as primer compositions, have been developed that have desirable chip resistance and/or corrosion resistance properties. Such chip resistant primer compositions may be placed directly upon a metal substrate or between an electrodeposited primer layer, which is directly upon the metal substrate, and an outer topcoat layer.
In the automotive refinish industry, several steps are often involved in repairing defects in the original coating. For example, such a repair can involve sanding or grinding out the defect by mechanical means, or completely stripping the whole part or vehicle of its original coating layers, often resulting in exposure of the bare metal substrate. The sanded area of exposed bare metal is then covered with a corrosion inhibitive primer composition, that is, a primer composition formulated with corrosion inhibitive pigments, such as strontium chromate, zinc phosphate, and derivatives of zinc phosphate, and which also adheres to both bare metal substrate and subsequently applied organic coatings. Next, a sandable primer-surfacer composition is often applied. Then, a primer, often referred to as a sealer, is applied, which improves adhesion of topcoats to the undercoated area, and also often improves the surface properties, such as chip resistance, of the entire coating system.
As is apparent, such a refinish undercoat application process can be time consuming and expensive due to labor, volatile organic abatement engineering requirements, and time required for drying of each of the applied undercoatings. As a result, it would be desirable to provide a coating composition that can exhibit favorable chip resistance and intercoat adhesion and which may allow for simplified methods of refinishing the surface of an article, such as an automobile body.